Apparatus for treating mill rolls



March 24, 1931. c, LOGAN APPARATUS FOR TREATTNG MILL. ROLLS Filed Feb. 23, 1929 INVENTCR i W) m PM W- Patented Meiru24il931 CHARLES rgnoeAat-or' reun'ron, MAssAoHusnrrs, 'Assrenon 1 0 w ns ELncrRrc I srnnr. CORPORATION, or rrrrsnunerr; PENNSYLVANIA; A conroaarronor r'nm'r- .APPARATUS FOR rnEA'riNe iirtr. norms Application filetl February 23,1929, Serial ma -341,920..-

J relates to apparatus for treating mill rolls and more'particularly to the heat treatment ofsuch rolls; 1 1

I In the art of manufacturing steel rolls of p 5 the character'utili'zed in rolling mills, it is 7 customary to cast J a steel ingot, forge the same, thereafter subject. the forged shape to a normalizing treatment under proper temperature conditions, and then the normalized shapeis rough-turned andoil-quenched pre-' paratory to a rough grinding. After roughgrinding it is subjected to a hardening process at a temperature of from 1550" to 1575 F.,"which gives a scleroscope hardness of around-110, As this hardness is too high for most rolling operations, it is customary to subject the roll to a drawing operation, after whichfit s given a finish grind.

Such rolls are of considerc ble diameter and are of considerable length; The overall length ofsuch rolls is a matter of several feet.-

The drawing operation is usually carried out by inserting the roll in a vertical position into a bath ofoilQ The depth ofsuch a bath is considerable. and a temperature gradient exists between the oil at the top of the tank and the oil at the bottom of the tank. As the temperature ofthe oil. bath is hotterat the bottom than at the top, imperfect tempering and drawing of the rolls has resulted, because the resulting degrees of hardness along the rolls vary with the temperature gradient in the bath.

When such a roll is placed in operation it wears unevenly. If one end. of theroll is too soft it wears away in use and if too hard it is liable to crack. Where unequal wearing c takes place along the roll and sheet metal is being rolled, there is a likelihood of sheets being thicker along one edge than along the other. V

position in a shallow tank. The depth of the tank is preferably made such as to just insure. that the roll is completelysubmerged and it is'poss'ible to maintain such ashallow I bath at substantially a uniform temperature as distinguished from having the tempera .turelgradient which; exists where the severalfeet high. .I '1

LI lso provide;meansforrotating the roll while it is suspended in the bath. The rela tive positions of, theends-of a roll inthe bath can be adjusted'so that-small tempera turejdi'fierences which might existin the bath H are-compensated for; The bath'is heated by a source ofthermal 'energysuch as a'burner; The accompanying drawings illustrate the present preferredembodiment of the inventionyin'whicli 1 x r Figure 1 is a longitudinal view partially in elevation: andpartially in section'of heat trecuting apparatus embodying my invention; an

Figure 2 is a transverse sectional View" thereoftaken substantially along theys'ection gReferring tofthe drawirigala roll 2 is-sus-l endediin"ahorizontal position in a tank?) contain ng abath of heat treating liquid 4 by chains or slingsfi vdriven by sprocket movement is given the shaft 7 by a sprocket wheel 8 and a drive chain 9 connected to any source of power](not shown). v 1 I The shaft is supported by brackets 10 and 11. The bracketsglO are movable along a guideway-12 formed in'ja supporting 'struc ture 14. fThe supporting structure 14 may-be v Wheels'fi mountedon a shaft'Z. Rotational lengths of the rolls 2 vary considera'bly,al- 7 overall length of substantially nine feet. The

thoughitheyare frequently madegwith an ends 15 of therolls are reduced for engagement with journals; The chains over theends 15,0fthe roll."

5 are slipped 1 The brackets 10 and 11. are two parts which are providedwith cooperating teeth -16] and are provided with slots 17' through whi'ehclamping bolts 18extend. Byw

adjusting the bracketslO and 11 bvmeans of the clamping bolts 18, 'the en'ds 'ofjthef shaft 7 may be moved vertically so that the pos1-' tions of the ends of the roll 2 may be varied slightly should it be found that the temperature of the bath 4 varies slightly at the ends thereof and at different distances from the. tank bottom. 7 As the diameters of the rolls 2 are frequently of a magnitude in excess of a foot, a diameter of fourteen inches being not uncommon, the depth of the tank 3 is made such that the bath {i completely covers the roll when, the roll is positioned in the tank. Where a roll having a fourteen inch diameter is being treated, a tankhaving a heightof eighteen inches is satisfactory.

It is to be understood that the foregoing numerical values are given byway of illustration of the invention and :notby way of limitation, as the specific dimensions may be varied in accordancewith the sizes of the rolls being treated.

The temperature of the bath l is maintained by a burner 19 disposed beneath the bath. By using a relatively shallowbath it is possible to maintain the temperature throughout the bath substantially uniform.

Small differences in temperature between the ends of the bath may be compensated for by adjusting the relative positions of the brackets 1O and 11, although when the burner 19 provides a uniform flame throughout its length such adjustments are usually unnecessary.

' If the supporting structure 14: is a traveling crane the chains 5 are placed over the ends 15 of the roll for lifting and conveying the roll to the bath. After th roll is in the bath'the shaft 7 is rotated to cause the roll 2 to slowly turn in the bath as the chains 5 comprising slings extending into the tank,

means'for imparting a turning movement to and-means permitting relative adjustments of the slings in a vertical plane In testimony whereof I have hereunto set m hand.

y CHARLES LOGAN.

move. By rotating the roll while in the 7 bath, all portions of the roll are-subjected to the same heat treatment. Hence the possibility of one part of the roll remaining in a Zone of different temperature than'another part is eliminated. A roll so treated is sub jeoted to uniform temperature throughout its length, thereby insuring a uniform drawing temperature throughout the roll.

While I have shown and described the present preferred embodiment ofthe invention, it is to be understood that it be otherwise embodied within the spirit of the invention and the scope of the appended claims. 7

I claim 7 -1 -Heat treating apparatus for rolls'comprising a horizontally extending "shallow tank, means for heating the tank, a shaft, driving members mounted on the shaft, vertically and longitudinally adjustable supports for said members, and slings depending from said driving members for supporting a d otati g a r l W ile s bme g d n 2. Heat treating apparatus comprising a tank, means for supporting a roll in the tank 

